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| Titel |
Correlation of Pc5 wave power inside and outside themagnetosphere during high speed streams |
| VerfasserIn |
R. L. Kessel, I. R. Mann, S. F. Fung, D. K. Milling, N. O'Connell |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 22, no. 2 ; Nr. 22, no. 2 (2004-01-01), S.629-641 |
| Datensatznummer |
250014787
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| Publikation (Nr.) |
 copernicus.org/angeo-22-629-2004.pdf |
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| Zusammenfassung |
We show a clear correlation between the ULF wave power (Pc5 range) inside and
outside the Earth's magnetosphere during high speed streams in 1995. We trace
fluctuations beginning 200RE upstream using Wind data, to fluctuations
just upstream from Earth's bow shock and in the magnetosheath using Geotail
data and compare to pulsations on the ground at the Kilpisjarvi ground
station. With our 5-month data set we draw the following conclusions. ULF
fluctuations in the Pc5 range are found in high speed streams; they are
non-Alfvénic at the leading edge and Alfvénic in the central region.
Compressional and Alfvénic fluctuations are modulated at the bow shock,
some features of the waveforms are preserved in the magnetosheath, but
overall turbulence and wave power is enhanced by about a factor of 10.
Parallel (compressional) and perpendicular (transverse) power are at
comparable levels in the solar wind and magnetosheath, both in the
compression region and in the central region of high speed streams. Both the
total parallel and perpendicular Pc5 power in the solar wind (and to a lesser
extent in the magnetosheath) correlate well with the total Pc5 power of the
ground-based H-component magnetic field. ULF fluctuations in the
magnetosheath during high speed streams are common at frequencies from
1–4mHz and can coincide with the cavity eigenfrequencies of 1.3, 1.9, 2.6,
and 3.4mHz, though other discrete frequencies are also often seen.
Key words. Interplanetary physics (MHD waves and turbulence)
– Magnetospheric physics (solar wind-magnetosphere
interactions; MHD waves and instabilities) |
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